Identifying and using independent sources (also called third-party sources) helps editors build non-promotional articles that fairly portray the subject, without undue attention to the subject's own views. Using independent sources helps protect the project from people using Wikipedia for self-promotion, personal financial benefit, and other abuses. Reliance on independent sources ensures that an article can be written from a balanced, disinterested viewpoint rather than from the subject's own viewpoint or from the viewpoint of people with an axe to grind. Emphasizing the views of disinterested sources is necessary to achieve a neutral point of view in an article. It also ensures articles can catalog a topic's worth and its role and achievements within society, rather than offering a directory listing or the contents of a sales brochure.

In determining the type of source, there are three separate, basic characteristics to identify:

Every possible combination of these three traits has been seen in sources on Wikipedia. Any combination of these three traits can produce a source that is usable for some purpose in a Wikipedia article. Identifying these characteristics will help you determine how you can use these sources.

This page deals primarily with the second question: identifying and using independent and non-independent sources.

An independent source is a source that has no vested interest in a given Wikipedia topic and therefore is commonly expected to cover the topic from a disinterested perspective. Independent sources have editorial independence (advertisers do not dictate content) and no conflicts of interest (there is no potential for personal, financial, or political gain to be made from the existence of the publication).

Interest in a topic becomes vested when the source (the author, the publisher, etc.) develops any financial or legal relationship to the topic. An interest in this sense may be either positive or negative. An example of a positive interest is writing about yourself, your family, or a product that is made or sold by your company or employer; an example of a negative interest is owning or working for a company that represents a competing product's article. These conflicts of interest make Wikipedia editors suspect that sources from these people will give more importance to advancing their own interests (personal, financial, legal, etc.) in the topic than to advancing knowledge about the topic. Sources by involved family members, employees, and officers of organizations are not independent.

Independence does not imply even-handedness. An independent source may hold a strongly positive or negative view of a topic or an idea. For example, a scholar might write about literacy in developing countries, and he may personally strongly favor teaching all children how to read, regardless of gender or socioeconomic status. Yet if the author gains no personal benefit from the education of these children, then the publication is an independent source on the topic.

Material available from sources that are self-published, primary sources, or biased because of a conflict of interest can play a role in writing an article, but it must be possible to source the information that establishes the subject's real-world notability to independent, third-party sources. Reliance on independent sources ensures that an article can be written from a balanced, disinterested viewpoint rather than from the person's own viewpoint. It also ensures articles can catalogue a topic's worth, its role and achievements within society, rather than offering a directory listing or the contents of a sales brochure.

Articles that don't reference independent sources should be tagged with {{third-party}}, and if no substantive coverage in independent reliable secondary sources can be identified then the article should be nominated for deletion. If the article's content is strictly promotional, it should even be made a candidate for speedy deletion under criterion WP:CSD G11.

Wikipedia strives to be of the highest standard possible, and to avoid writing on topics from a biased viewpoint. Wikipedia:Verifiability was created as an expansion of the neutral point of view policy, to allow information to be checked for any form of bias. It has been noticed, however, that some articles are sourcing their content solely from the topic itself, which creates a level of bias within an article. Where this primary source is the only source available on the topic, this bias is impossible to correct. Such articles tend to be vanity pieces, although it is becoming increasingly hard to differentiate this within certain topic areas.

If Wikipedia is, as defined by the three key content policies, an encyclopaedia which summarises viewpoints rather than a repository for viewpoints, to achieve this goal, articles must demonstrate that the topic they are covering has been mentioned in reliable sources independent of the topic itself. These sources should be independent of both the topic and of Wikipedia, and should be of the standard described in Wikipedia:Reliable sources. Articles should not be built using only vested-interest sources. This requirement for independent sources is so as to determine that the topic can be written about without bias; otherwise the article is likely to fall foul of our vanity guidelines.

In the case of a Wikipedia article about a website, for example, independent sources would include an article in a newspaper which describes the site, but a reference to the site itself would lack independence (and would instead be considered a primary source).

Examples of independent and non-independent sources for some common subjects

Mayor's website, local booster clubs, local chamber of commerce website

a book, music recording, movie

Newspaper or magazine review, book (or chapter)

Production company website, publishing company website, website for the book/album/movie, album sleeve notes, book jacket copy, autobiography by the musician, actor, etc.

These simple examples need to be interpreted with all the facts and circumstances in mind. For example, a newspaper that depends on advertising revenue might not be truly independent in their coverage of the local businesses that advertise in the paper. As well, a newspaper owned by person X might not be truly independent in its coverage of person X and her business activities.

Every article on Wikipedia must be based upon verifiable statements from multiple third-party reliable sources with a reputation for fact-checking and accuracy. A third-party source is one that is entirely independent of the subject being covered, e.g., a newspaper reporter covering a story that they are not involved in except in their capacity as a reporter. The opposite of a third-party source is a first-party or non-independent source. A first-party, non-independent source about the president of an environmental lobby group would be a report published by that lobby group's communications branch. A third-party source is not affiliated with the event, not paid by the people who are involved, and not otherwise likely to have a conflict of interest related to the material.

This concept is contrasted with the unrelated concept of a secondary source, which is one where the material presented is based on some other original material, e.g., a non-fiction book analyzing original material such as news reports, and with a primary source, where the source is the wellspring of the original material, e.g., an autobiography or a politician's speech about his or her own campaign goals. Secondary does not mean third-party, and primary does not mean non-independent or affiliated with the subject. Secondary sources are often third-party or independent sources, but they are not always third-party sources.

Although there is technically a small distinction between a third-party source and an independent one, most of Wikipedia's policies and guidelines use the terms interchangeably, and most sources that are third-party also happen to be independent. Note that a third party is not necessarily independent. For example, if famous filmmaker Y has a protege who runs a film review website ("Fully Independent Critic.com"), and if filmmaker Y instructs "Independent Critic" to praise or attack film Q, then filmmaker and Y and Fully Independent Critic.com might not be independent, even though they are not related by ownership, contract or any legal means.

Independent sources are a necessary foundation for any article. Although Wikipedia is not paper, it is also not a dumping ground for any and all information that readers consider important or useful. For the sake of neutrality, Wikipedia cannot rely upon any editor's opinion about what topics are important. Everything in Wikipedia must be verified in reliable sources, including statements about what subjects are important and why. To verify that a subject is important, only a source that is independent of the subject can provide a reliable evaluation. A source too close to the subject will always believe that the subject is important enough to warrant detailed coverage, and relying exclusively upon this source will present a conflict of interest and a threat to a neutral encyclopedia.

Arguably, an independent and reliable source is not always objective enough or knowledgeable to evaluate a subject. There are many instances of biased coverage by journalists, academics, and critics. Even with peer review and fact-checking, there are instances where otherwise reliable publications report complete falsehoods. But Wikipedia does not allow editors to improve an article with their own criticisms or corrections. Rather, if a generally reliable source makes a false or biased statement, the hope is that another reliable source can be found to refute that statement and restore balance. (In severe cases, a group of editors will agree to remove the verified but false statement, but without adding any original commentary in its place.)

If multiple reliable publications have discussed a topic, or better still debated a topic, then that improves the topic's probability of being covered in Wikipedia. First, multiple sources that have debated a subject will reliably demonstrate that the subject is worthy of notice. Second, and equally important, these reliable sources will allow editors to verify certain facts about the subject that make it significant, and write an encyclopedic article that meets our policies and guidelines.

The Bippledorp 9000's man­u­fac­turer calls it "a landmark in the history of music and the most leg­end­ary pedal in rock"; an in­de­pend­ent magazine review may call it "a meh".

Non-independent sources may be used to source content for articles, but the connection of the source to the topic must be clearly identified. i.e. "The organization X said 10,000 people showed up to protest." is OK when using material published by the organization, but "10,000 people showed up to protest." is not. Similarly, saying "Pax-Luv's manufacturer, Umbrella Cor., says Pax-Luv is the top tranquilizer", but "Pax-Luv is the top tranquilizer" (without attribution) is undesirable.

A press release is clearly not an independent source as it is usually written either by the business or organization it is written about, or by a business or person hired by or affiliated with the organization (e.g., a spin doctor). Press releases commonly show up in Google News searches and other searches that editors commonly use to locate reliable sources. Usually, but not always, a press release will be identified as such. Many less reputable news sources will write an article based almost exclusively on a press release, making only minor modifications. When using news sources whose editorial integrity you are uncertain of, and an article reads like a press release, it is crucial to check to see that the source is not simply recycling a press release (a practice called "churnalism"). Sometimes, but not always, it is possible to locate the original press release used to generate the article.

In general, press releases have effusive praise, rather than factual statements. A press release about the Bippledorp 9000 effect pedal by its manufacturer might call it the "greatest invention in the history of electric guitar"; in contrast, an independent review in Guitar Player magazine may simply make factual statements about its features and call it an "incremental tweak to existing pedal features".

There are companies that generate television segments and sell them to broadcasters – this is broadcast syndication. This also happens in in printed media and across websites. A syndication company may offer the same story in multiple formats, such as a long and short news article, or the same story with an alternate lead, or a video and a written article. Whatever the length or format, they usually contain the same claims and are written or edited by the same person or team.

Syndicated news pieces may be independent of the subject matter, but they are not independent of one another. When considering notability or due weight within an article, all of the related articles by the same publishing syndicate, no matter how widely they were sold, are treated as the same single source. (See also: Wikipedia:Notability#cite ref-3.)

Any publication put out by an organization is clearly not independent of any topic that organization has an interest in promoting. In some cases, the conflict of interest is easy to see. For example, in an article about a chemical spill by Foo Petrochemicals Inc., an article by Foo Petrochemicals about how "green", nature-loving and environment-saving their company is not independent. If the pro-Foo Petrochemicals source is written by Foo itself or by a public relations firm hired by Foo, in both cases, Foo and the hired PR firm have a conflict of interest in favour of Foo Inc.

However, less direct interests can be harder to see and more subjective to establish. Continuing with this Foo Inc. example, what if a non-profit organization named "Grassroots Reach-out Accountability Sustainability " ("GRASS") writes a press release calling Foo Petrochemicals the #1 savior of the environment and the planet. Does GRASS have a conflict of interest? Well, the GRASS.com website says GRASS is 100% independent and community-based. However, closer research may reveal that GRASS was astroturfed by certain unnamed wealthy benefactor corporations who gave the organization lots of money to pursue these "independent" agendas.

Much scientific research is often funded by companies with an interest in the outcome of the experiments, and such research makes its way into peer-reviewed journals. For example, pharmaceutical companies may fund research on their new medication Pax-Luv. If you are a scientist doing research on Pax-Luv, finding out adverse information about this drug will be adverse for your continued funding. Journals themselves can also have conflicts of interest due to their funding sources. Caution must be used in accepting sources as independent. While the peer-review process ensures greater independence, it does not guarantee independence of a source. This is especially true of controversial topics where there may be a great deal of debate and dissent, even in reliable sources.

When there is a potential conflict of interest, identifying the connection between the source and topic is important, such as by saying "A study by X found that Y." Rather than excluding such non-independent sources from a page, it is often best to include them, with mention of how the source is connected to someone with an interest in the topic.

Independence alone is not a guarantee that the source is accurate or reliable for a given purpose. Independent sources may be outdated, self-published, mistaken, or not have a reputation for fact-checking.

Outdated: A book from 1950 about how asbestos fibre insulation is 100% safe for your house's roof may be published by a source which is completely independent from the asbestos mining and asbestos insulation industries. However, as of 2018, this 1950 book is outdated.

Self-published: A book by a self-proclaimed "International Insulation Expert", Foo Barkeley, may claim that asbestos fibre insulation is totally safe, and that we should all have fluffy heaps of asbestos fibre in our roofs and walls. However, if Foo Barkeley has paid the vanity press company "You Pay, We Print It!" to print 100,000 copies of his treatise praising asbestos, then we don't know if Barkeley's views on asbestos are reliable.

Mistaken: The world's most elite effect pedal experts, the International Guitar Pedal Institute, may declare in 1989 that the "Bippledorp 9000 pedal is the first pedal to use a fuzz bass effect"; however, in 2018, new research may show that fuzz bass effects were available in pedal formats in the 1970s.

Not good reputation for fact-checking: A tabloid newspaper, the Daily Truth, may declare that a film celebrity, Fingel Stempleton, was kidnapped by space aliens and taken to their home planet for probing/surgery for the entire day of January 1, 2018. DT may make this claim based on an interview with a guest at Stempleton's mansion who witnessed the UFO's arrival in the gated Stempleton mansion/compound. However, a major newspaper with a reputation for fact-checking counters this claim with the release of 60 days of police video surveillance showing Stempleton was locked up for drunk driving for from December 1, 2017 to January 30, 2018. (Hmmm, perhaps Stempleton used a Jedi astral travel trick to get out of lockup?)

Non-independent sources may not be used to establish notability. The core policy Wikipedia:What Wikipedia is not requires that it be possible to verify a subject with at least one independent source, or else the subject may not have a separate article in Wikipedia. There is no requirement that every article currently contain citations to such sources, although it is highly desirable.

Some sources, while apparently independent, are indiscriminate sources. For example, a travel guide might attempt to provide a review for every single point of interest, restaurant, or hotel in a given area. A newspaper in a small town might write about the opening and closing of every single business in the town, or the everyday activities of local citizens. An enthusiastic local music reviewer may pen a review of every single person who comes on stage in their town with a guitar and a microphone, whether it is an amateur garage band playing for the first time or a major touring group. Sometimes, WP editors think that because a reliable source mentions a certain band, book, film or other topic, this confers notability on the book, film or other topic. Not necessarily. The New York Times may state that Foo Barkeley was onstage at a rock concert ("Foo Barkeley was one of the opening acts who performed on May 1, 2017 at the venue". This is arguably a "bare mention"; yes the NYT says that Foo performed, but they don't say whether the concert was good or noteworthy.

Indiscriminate but independent sources may be reliable – for example, an online travel guide may provide accurate information for every single hotel and restaurant in a town – but the existence of this information should be considered skeptically when determining due weight and whether each of the mentioned locations qualifies for a separate, standalone article. If a subject, such as a local business, is only mentioned in indiscriminate independent sources, then it does not qualify for a separate article on Wikipedia, but may be mentioned briefly in related articles (e.g., the local business may be mentioned in the article about the town where it is located).

An article that currently is without third-party sources should not always be deleted. The article may merely be in an imperfect state, and someone may only need to find the appropriate sources to verify the subject's importance. Consider asking for help with sources at the article's talk page, or at the relevant WikiProject. Also consider tagging the article with an appropriate template, such as {{Third-party}} or {{unreferenced}}.

If no amount of searching will remedy this lack of sources, then it may still be possible to preserve some of the information by merging it into another broad topic. But in order to avoid undue weight, the subject may first need to be summarized appropriately. Consider starting a merge discussion, using the template {{merge}}.

Use the {{prod}} tag, for articles which do not meet the criteria for speedy deletion, but are uncontroversial deletion candidates. This allows the article to be deleted after seven days if nobody objects. For more information, see Wikipedia:Proposed deletion.

For cases where you are unsure about deletion or believe others might object, nominate the article for the articles for deletion process, where the merits will be debated and deliberated for at least seven days.

Some articles do not belong on Wikipedia, but fit one of the Wikimedia sister projects. They may be copied there using transwiki functionality before considering their merger or deletion. If an article to be deleted is likely to be re-created under the same name, it may be turned into a soft redirect to a more appropriate sister project's article.

This concept is contrasted with the unrelated concept of a secondary source. A secondary source derives its material from some other, original material, e.g., a non-fiction book analyzing original material such as news reports. Secondary sources are contrasted with primary sources. Primary sources are the wellspring of the original material, e.g., an autobiography or a politician's speech about his or her own campaign goals. Secondary does not mean independent, and primary does not mean non-independent or affiliated with the subject. Secondary sources are often third-party or independent sources, but not always.

This concept is unrelated to whether a source is self-published. A self-published source is made available to the public ("published") by or at the direction of the person or entity that created it. Blog posts by consumers about their personal experiences with a product are completely independent, self-published sources. A peer-reviewed article in an reputable academic journal by researchers at a pharmaceutical company about one of their products is a non-independent, non-self-published source.

It doesn't matter if you love it or hate it. If you aren't selling it, you're probably an independent source about it.

A source can be biased without compromising its independence. When a source strongly approves or disapproves of something, but it has no connection to the subject and does not stand to benefit directly from promoting that view, then the source is still independent.

In particular, many academic journals are sometimes said to be "biased", but the fact that education journals are in favor of education, pharmaceutical journals are in favor of pharmaceutical drugs, journals about specific regions write about the people and places in that region, etc., does not mean that these sources are non-independent, or even biased. What matters for independence is whether they stand to gain from it. For example, a drug company publishing about their own products in a pharmaceutical journal is a non-independent source. The same type of article, written by a government researcher, would be an independent source.

There is technically a small distinction between a third-party source and an independent one. An "independent" source is one that has no vested interest in the subject. For example, the independent source will not earn any extra money by convincing readers of its viewpoint. A "third-party" source is one that is not directly involved in any transaction related to the subject, but may still have a financial or other vested interest in the outcome. For example, if a lawsuit between two people may result in one person's insurance company paying a claim, then that insurance company is a third party but is not financially independent.

However, most of Wikipedia's policies and guidelines use the terms interchangeably, and most published sources that are third-party also happen to be independent. Except when directly specified otherwise in the policy or guideline, it is sufficient for a source to be either independent or third-party, and it is ideal to rely on sources that are both.

Wikipedia's policy on What Wikipedia is not states that "All article topics must be verifiable with independent, third-party sources".

Wikipedia's policies on both Verifiability and No original research state that "If no reliable, third-party sources can be found for an article topic, Wikipedia should not have an article on it."

Wikipedia's policy on Verifiability states that "Articles should be based upon reliable, third-party published sources with a reputation for fact-checking and accuracy."

Wikipedia's guideline on Reliable sources states that "Wikipedia articles should rely primarily on reliable, third-party, published sources".

Wikipedia's guideline on Notability states that "If a topic has received significant coverage in reliable sources that are independent of the subject, it is presumed to satisfy the inclusion criteria for a stand-alone article."

An article must be based upon reliable third-party sources, and meets this requirement if:

Reliable: A third-party source is reliable if it has standards of peer review and fact-checking. In general, the more people engaged in checking facts, the more reliable the publication.

Third-party: A third-party source is independent and unaffiliated with the subject, thus excluding first-party sources such as self-published material by the subject, autobiographies, and promotional materials.

Sources: At least two third-party sources should cover the subject, to avoid idiosyncratic articles based upon a single perspective.

Based upon: These reliable third-party sources should verify enough facts to write a non-stub article about the subject, including a statement explaining its significance.

Once an article meets this minimal standard, additional content can be verified using any reliable source. However, any information that violates What Wikipedia is not must be removed, regardless of whether or not it is verified in reliable third-party sources.